Limiting Factors



Columbia Cascade Province

Methow Subbasin 402, 404

Bull Trout
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Food Competition -- Species Management Species Introduction Juveniles, adults Introduction of brook trout threatens bull trout through competition and hybridization.
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization; Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Two passage barriers (culverts) exist in the lower 3.5 miles of the Black Canyon/Squaw Creek. Methow Valley Irrigation District canal diversion and culverts are impediments in the Lower Twisp. Flow diversions are present in the Lower Chewuch River as well as culverts in Cub and Little Boulder creeks (Lower Chewuch River). A road confinement velocity barrier exists in Eightmile Creek.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles, adults Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles, adults Loss of riparian vegetation is prevalent throughout the subbasin.
Instantaneous Mortality Predation -- Species Management Species Introduction Juveniles, adults Walleye and smallmouth bass prey on salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; All Increased sediment load and high percentage of fines exists in the depositional areas. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
Water Quantity Increased Water Quantity; Decreased Water Quantity -- Forest Management Water: Storage or Withdrawal Juveniles, adults Increased peak flows and increased flashy flows exist due to fires in the headwaters. Low flows persist due to natural losing at river mile 0-4.3 on Wolf Creek.
Coho
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Decreased Water Quantity; Morphological Changes Freshwater - Floodplain Agricultural Practices; Urbanization Diking; Impervious Surfaces; Riparian Degradation Juveniles Loss of connection to the floodplain due to roads and riprap in the first reach of Early Winters Creek and Lost River. High road densities exist in Little Bridge, Poorman, and Buttermilk creeks. Loss of connection to the floodplain in the lower 800 feet of Wolf Creek and the loss of riparian vegetation in the lower mile of Goat Creek/Little Boulder limit productivity.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles Loss of riparian vegetation is prevalent throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Coho are subject to ocean and fresh water harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass nine mainstem dams during migration.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; All Increased sediment load and high percentage of fines exists in the depositional areas. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
SPRING CHINOOK
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization; Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Two passage barriers (culverts) exist in the lower 3.5 miles of the Black Canyon/Squaw Creek. Methow Valley Irrigation District canal diversion and culverts are impediments in the Lower Twisp. Flow diversions are present in the Lower Chewuch River as well as culverts in Cub and Little Boulder creeks (Lower Chewuch River). A road confinement velocity barrier exists in Eightmile Creek.
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Decreased Water Quantity; Morphological Changes Freshwater - Floodplain Agricultural Practices; Urbanization Diking; Impervious Surfaces; Riparian Degradation Juveniles Loss of connection to the floodplain due to roads and riprap in the first reach of Early Winters Creek and Lost River. High road densities exist in Little Bridge, Poorman, and Buttermilk creeks. Loss of connection to the floodplain in the lower 800 feet of Wolf Creek and the loss of riparian vegetation in the lower mile of Goat Creek/Little Boulder limit productivity.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles Loss of riparian vegetation is prevalent throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Spring Chinook are subject to fresh water harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass nine mainstem dams during migration.
Instantaneous Mortality Competition; Pathogens -- Artificial Propagation Hatchery Fish Production; Disease Amplification and Transfer Juveniles Competition, genetic introgression, and disease transmission from hatchery introductions may reduce productivity.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian; Predators: Marine Mammal Juveniles Avian and pinniped predation are concerns. Walleye and smallmouth bass prey on salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; Juveniles Increased sediment load and high percentage of fines exists in the depositional areas. Water temperatures limit spring Chinook spawning and incubation from river mile 0-4 in the Lower Twisp. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
Summer Chinook
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization; Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Two passage barriers (culverts) exist in the lower 3.5 miles of the Black Canyon/Squaw Creek. Methow Valley Irrigation District canal diversion and culverts are impediments in the Lower Twisp. Flow diversions are present in the Lower Chewuch River as well as culverts in Cub and Little Boulder creeks (Lower Chewuch River). A road confinement velocity barrier exists in Eightmile Creek.
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Decreased Water Quantity; Morphological Changes Freshwater - Floodplain Agricultural Practices; Urbanization Diking; Impervious Surfaces; Riparian Degradation Juveniles Loss of connection to the floodplain due to roads and riprap in the first reach of Early Winters Creek and Lost River. High road densities exist in Little Bridge, Poorman, and Buttermilk creeks. Loss of connection to the floodplain in the lower 800 feet of Wolf Creek and the loss of riparian vegetation in the lower mile of Goat Creek/Little Boulder limit productivity.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles Loss of riparian vegetation is prevalent throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Instantaneous Mortality Anthropogenic Mortality -- Fishery Management Harvest Adults Spring Chinook are subject to fresh water harvest.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass nine mainstem dams during migration.
Instantaneous Mortality Competition; Pathogens -- Artificial Propagation Hatchery Fish Production; Disease Amplification and Transfer Juveniles Competition, genetic introgression, and disease transmission from hatchery introductions may reduce productivity.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian; Predators: Marine Mammal Juveniles Avian and pinniped predation are concerns. Walleye and smallmouth bass prey on salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; Juveniles Increased sediment load and high percentage of fines exists in the depositional areas. Water temperatures limit spring Chinook spawning and incubation from river mile 0-4 in the Lower Twisp. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
SUMMER STEELHEAD
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization; Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Two passage barriers (culverts) exist in the lower 3.5 miles of the Black Canyon/Squaw Creek. Methow Valley Irrigation District canal diversion and culverts are impediments in the Lower Twisp. Flow diversions are present in the Lower Chewuch River as well as culverts in Cub and Little Boulder creeks (Lower Chewuch River). A road confinement velocity barrier exists in Eightmile Creek.
Habitat Quantity and Quality Access and Availability; Morphological Changes Estuary Agricultural Practices; Urbanization Diking; Filling; Riparian Degradation; Wetland Loss Smolts Historical complex habitats have been modified through channelization, diking, development and other practices.
Habitat Quantity and Quality Decreased Water Quantity; Morphological Changes Freshwater - Floodplain Agricultural Practices; Urbanization Diking; Impervious Surfaces; Riparian Degradation Juveniles Loss of connection to the floodplain due to roads and riprap in the first reach of Early Winters Creek and Lost River. High road densities exist in Little Bridge, Poorman, and Buttermilk creeks. Loss of connection to the floodplain in the lower 800 feet of Wolf Creek and the loss of riparian vegetation in the lower mile of Goat Creek/Little Boulder limit productivity.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles Loss of riparian vegetation is prevalent throughout the subbasin.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Instantaneous Mortality Anthropogenic Mortality -- Dam or Hydropower Facility Management Migration Impediments Juveniles Juveniles and adults must pass nine mainstem dams during migration.
Instantaneous Mortality Competition; Pathogens -- Artificial Propagation Hatchery Fish Production; Disease Amplification and Transfer Juveniles Competition, genetic introgression, and disease transmission from hatchery introductions may reduce productivity.
Instantaneous Mortality Predation -- Dam or Hydropower Facility Management; Species Management Predators: Fish; Predators: Avian; Predators: Marine Mammal Juveniles Avian and pinniped predation are concerns. Walleye and smallmouth bass prey on salmonids.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; Juveniles Increased sediment load and high percentage of fines exists in the depositional areas. Water temperatures limit spring Chinook spawning and incubation from river mile 0-4 in the Lower Twisp. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
WESTSLOPE CUTTHROAT
Key Limiting Factor Impairment Habitat Affected Threat Type Threat Name Life Stage (s) Description
Habitat Quantity and Quality Access and Availability Freshwater-Instream Agricultural Practices; Forest Management; Urbanization; Dam or Hydropower Facility Management Migration Impediments Juveniles, adults Two passage barriers (culverts) exist in the lower 3.5 miles of the Black Canyon/Squaw Creek. Methow Valley Irrigation District canal diversion and culverts are impediments in the Lower Twisp. Flow diversions are present in the Lower Chewuch River as well as culverts in Cub and Little Boulder creeks (Lower Chewuch River). A road confinement velocity barrier exists in Eightmile Creek.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Instream Agricultural Practices; Forest Management; Urbanization Riparian Degradation; Bank Destabilization Juveniles, adults Lack of large woody debris exists throughout the subbasin as well as high embeddedness in spawning habitat. There has been a loss of quality pools and large woody debris in Little Boulder Creek and the gorge in Goat Creek.
Habitat Quantity and Quality Small-Scale Structural Complexity; Morphological Changes Freshwater-Riparian Agricultural Practices; Forest Management; Urbanization Riparian Degradation Juveniles, adults Loss of riparian vegetation is prevalent throughout the subbasin.
Sediment Conditions Increased Sediment Quantity Freshwater-Instream Agricultural Practices; Urbanization Impervious Surfaces; Sediment: Bank Destabilization; All Increased sediment load and high percentage of fines exists in the depositional areas. Increased sediment load below Buttermilk Creek (Lower Twisp) is problematic.
Water Quantity Increased Water Quantity; Decreased Water Quantity -- Forest Management Water: Storage or Withdrawal Juveniles, adults Increased peak flows and increased flashy flows exist due to fires in the headwaters. Low flows persist due to natural losing at river mile 0-4.3 on Wolf Creek.